The invention relates generally to rack lubricating systems, and specifically, to machine assemblies employing exposed racks, where excess lubricant is not permissible.
One area where excess lubricant is not permitted is on machines which may utilize overhead rack assemblies where excess lubricant would tend to drip onto a shop floor; personnel; or a workpiece.
In the aerospace industry and in other industries, parts are being manufactured from composite tape comprised of reinforcing fibers impregnated with a resin. Tape machines have been developed which carry an elevated tape laying head. The tape laying head dispenses composite tape as it makes multiple passes across a mold or work surface. The tape laying machines utilized for making composite structures are located in a "clean room"; that is, a room which is free of dust and other contaminants so that the successive plys of built-up composite material will be free of deleterious matter. In such an environment, it is not permitted to have stray lubricant contaminating the machine locale.
It may be appreciated that a lubricator is required for rack and pinion drives, to prevent break down and galling of the toothed surfaces, especially for machines having high loads or requiring high speed of operation. Tape laying machines generally are lightweight and operate at moderately high speeds.
The requirement of rack lubrication on rack and pinion drives is deemed to be of importance in other industries as well, such as the food and soft drink industries, where food contaminants such as lubricating oil are not permitted.
It is well known in the gear industry to employ mist lubrication for gear drives, but it is necessary to enclose the mist of air and oil to prevent contamination of the environment. Some mist lubrication systems require oil reclassifiers or oil reclamation devices on an enclosed housing.
Similarly, it is well known that many enclosed rack and pinion drives are flooded with liquid lubricant, either statically or by means of an oil pump.
On a gantry type tape laying machine, it is preferable to use a rack and pinion drive to feed the tape head gantry along a slideway, which may extend up to sixty feet, or more. Such a machine utilizes a drive box having a drive pinion carried on the movable gantry and the relatively stationary rack is carried on a machine base either at a low point or a high point, elevated from the floor. Obviously, an oil flood system cannot be employed because of the magnitude of an enclosure and the quantity of oil needed to lubricant the system. Similarly, an oil mist system cannot be utilized because of the danger of airborne oil migrating to a composite surface, which must be free of contaminants.
Applicant has obviated the difficulties inherent in prior art systems for lubricating a rack and pinion drive, by means of a novel rack lubricator which is carried along with the movable drive pinion relative to a stationary rack.
It is therefore an object of the present invention to provide a rack lubricator which will provide a coating of lubricant to a rack surface utilizing a minimum quantity of coating lubricant.
Another object of the present invention is to provide a rack lubricator for use in overhead rack and pinion drive systems which will not contaminate a lower work surface with lubricant.